[8][14] There is some off-label use of oclacitinib in treating asthma and allergic dermatitis in cats, but the exact efficacy has not been established.

[10][15] New cutaneous or subcutaneous lumps, such as papillomas, can appear,[10][17] and dogs face an increased susceptibility to infections such as demodicosis.

[1][15] There is a transient decrease in neutrophils, eosinophils, and monocytes, as well as in serum globulin, while cholesterol and lipase levels increase.

[1][17][18] Less common side effects of oclacitinib include bloody diarrhea; pneumonia; infections of the skin, ear, and/or urinary tract; and histiocytomas (benign tumors).

[10][15] Oclacitinib is not a corticosteroid or antihistamine, but rather modulates the production of signal molecules called cytokines in some cells.

[13] Normally, a cytokine binds to a JAK (Janus kinase) receptor, driving the two individual chains to come together and self-phosphorylate.

[21] Oclacitinib is absorbed well when taken orally; it takes less than an hour to reach peak plasma concentration and has a bioavailability of 89%.